Electrical connection structures in additional unit for vehicles and in inner mirror

Disclosed is an electrical connection structure in an inner mirror, which facilitates installation of the inner mirror and establishment of the connection therein. A button (attachment) and a first current-carrying member are provided on a windshield. The inner mirror includes a base, a second current-carrying member and an electrical-power driven portion. When the base of the inner mirror is made to slide onto the button, connecting portions of the first and second current-carrying member come in contact with each other, so that they are electrically connected to each other. Consequently, the electrical-power driven portion is supplied with electrical power from a power source external to the inner mirror through the first and second current-carrying portions.